In this SBIR Phase I project the key mechanical properties of ultrahigh molecular weight polyethylene (UHMWPE) joint implant materials will be improved by creating a composite material with carbon reinforcements. UHMWPE has long been widely used in joint implants, and further improvements to its wear resistance have been obtained by cross-linking the polyethylene chains. However, the cross-linking process has also been associated with degradation of the mechanical properties, including toughness, fatigue and yield strengths. Incorporating carbon reinforcements into UHMWPE through the manner described will improve the strength and creep resistance of UHMWPE without compromising its low wear rate. The carbon reinforcements will impart unmatched dimensional stability and toughness to the UHMWPE matrix, providing that good load transfer occurs between the carbon and polymer. These hypotheses will be validated by preparing composite materials under various formation conditions, subjecting test specimens to various crosslinking conditions, and then assessing their mechanical and tribological properties. Should the new UHMWPE materials perform according as expected, the benefits would include longer-lasting implants that are less prone to catastrophic failure. PUBLIC HEALTH RELEVANCE: Joint implants are an effective treatment for those with rheumatoid arthritis, osteoarthritis, osteonecrosis, and other severe destructive injuries; within the U.S. alone, roughly 500,000 joint replacements are performed each year. As life expectancy increases, patients more frequently outlive the 10 to 15 year lifetime of their implant. This projet will introduce a new material from which prosthetics with longer lifetimes can be fabricated.